Packaging based on paper products are widely used world wide. The strength of paper products which are not water-repellant or water-proof are dependent on the humidity of the environment. An increase in the relative humidity from 50% to 80% decreases the strength measured as the load capacity of paper boxes made of a non-water-repellant paper product with about 90%.
Water-proof packaging or wrapping are generally used for packaged liquids and non-liquids which are sold in a large number world wide; however, the packaging material often is difficult to dispose of in a sustainable way.
Cellulose-based packaging materials have been used for storing liquids, in particular non-carbonated liquids. Thus, the use of TetraPak is a practical approach for using cellulose-based cartons for storing liquids. In these materials the fibers of the paper pulp are coated with a water resistant material, but the fibres of the paper pulp are not covalently anchored and chemically crosslinked because grafting is typically performed in organic solvent and is an expensive process in absence of the present invention.
The packaging materials based on cellulose as well as paper products used as water-proof packaging can be produced from products surface treated with compounds in a process including liquid solvents. The current materials are produced by impregnation of conventional cardboard sheets with different wax products and adhesive coating films.